Technical Field
The present invention relates to a light emitting device having a semiconductor light emitting element and a resin layer having an internal conductive member.
Description of Related Art
Light emitting devices having semiconductor chips (light emitting elements) such as light emitting diodes can facilitate miniaturization and obtain high luminous efficiency, which allows for their use in wide range of applications. For example, a light emitting device suitable for the backlight of a liquid crystal display such as a mobile phone is described in JP 2008-198807A. The light emitting device described in JP 2008-198807A is constituted with a light emitting element, lead frames to which the light emitting element is electrically connected, and a package made of a resin. An opening is defined in the front surface and exposing portions of the lead frames on its lower surface. The package is joined with a mounting substrate via the portions of the lead frames.
As described in JP2008-198807A, in a configuration where a face-up type light emitting element is mounted on a lead frame or the like and the light emitting element and the lead frame are connected with a bonding wire or the like, as seen perpendicularly to the upper surface, a part of the bonding wire is needed to be outside of the outer periphery of the light emitting element, which limits the downsizing. Also, packaging with the use of a lead frame itself imposes a limitation on downsizing of the light emitting device.
On the other hand, in the face-down type (which typically employs a flip-chip configuration), the pad electrode disposed on the light emitting element and the wiring disposed on the mounting substrate can be electrically connected with the use of a connecting means such as a bump or a metal pillar which is located inside the outer periphery of the light emitting element in a plan view seen from a vertical direction to the surface of the mounting substrate. With this configuration, CSP (Chip Size Package or Chip Scale Package) can be realized, in which the light emitting device (particularly the dimensions in a plan view seen from a vertical direction to the mounting surface of the mounting substrate) can be downsized to a degree that is close to the size of the light emitting element chip. Recently, in order to facilitate further downsizing or to obtain a further increase in the luminous efficiency, the light emitting devices of face-down type have been used, in which the growth substrate such as a light-transmissive substrate, an example being a sapphire substrate, has been removed, or the thickness of the growth substrate has been reduced.
The growth substrate is used to allow growing of an n-type semiconductor layer and a p-type semiconductor layer, which are constituent components of a light emitting element on its surface, and the growth substrate also has a function of improving the strength of the light emitting device by supporting the light emitting element, which has a small thickness and low mechanical strength. Thus, in a light emitting device in which after forming the light emitting element, the growth substrate is removed or the thickness of the growth substrate is reduced, for example, as shown in JP 2010-141176A, a resin layer is provided at the electrode side (a side facing the mounting substrate) to support the light emitting element, and a metal pillar which penetrates the resin layer is formed, and through the metal pillar, the electrode of the light emitting element and the wiring (wiring layer) disposed on the mounting substrate are electrically connected. With such a resin layer which contains such a metal pillar, the light emitting device can be secured with sufficient strength. Also, CSP is suitable for manufacturing on a wafer level (WCSP) where a plurality of packages are produced collectively on a wafer, which thus facilitates downsizing and enhances productivity.
There are two types of configurations for the light emitting devices used for backlight light source of liquid crystal displays or the like: a top-view type in which the mounting surface of the light emitting device is substantially in parallel to the incident surface of the light guide plate, and a side-view type in which the mounting surface is substantially perpendicular to the incident surface of the light guide plate.
In the case where CSPs are fabricated in a wafer level as in the light emitting device described in JP 2010-141176A, electrodes for external connection are disposed via a resin layer on the back-surface side of the light emitting element, which produce a top-view type of light emitting devices. On the other hand, a side-view type light emitting device can be produced, for example, as described in JP 2008-198807A, by packaging with lead frames formed to allow side-view type mounting. However, as described above, packaging with the use of lead frames imposes a limitation on downsizing of the light emitting device. Also, in the case where the light emitting devices are fabricated as CSPs as in JP 2010-141176A, the electrodes for external connection are needed to be formed on the side surfaces of the CSPs which are created as cleavage surfaces at the time of singulating the CSPs that are fabricated in a wafer level. For this reason, operations after singulation cannot be performed on a wafer-level, so that side-view-type mounting in wafer-level CSP has been difficult to be realized. Accordingly, an object of the present embodiment is to provide a CSP light emitting device which can be mounted in a side-view configuration and which can be manufactured on a wafer-level, and to provide a method of manufacturing the same.